Meanwhile, Jaquelline clearly did not understand and didn't want to. "It's more of her ridiculous nonsense! She's clearly demented. We need to lock her up for her own good."

Sam ignored her. "What is tepid fusion, Sara?"

"Well... I was reading up on cold fusion and the work with plasma and all that stuff in the physics magazines you got." Not exactly magazines. They were academic papers he was checking on an intellectual property case he'd been working on. "And I realised that cold fusion is bound to fail because the physics is only intellectually plausible. If it was just a little warmer... Um. And then I remembered about a guy who tried to make a reactor in his shed? So I got all the precautions in before I started messing around with fire alarms."

"Fire alarms," Sam repeated. He recognised Sara's rapid-fire talking as an attempt to get as much information across in as little time as she could.

"It turns out that it can be self-sustaining, after a while. The fissionable material also fuels the fusion reaction. You don't even need heavy water! Just the regular stuff from the tap will do. Even the gold that comes out isn't radioactive, it's amazing." Her happy smile faded. "I'm still working out the math, sadly."

"Gold," echoed Jaquelline. Going straight for the one thing that could change her mind. "You're making... gold."

"I posit that it's the heaviest stable atom that's viable at the temperatures I have it at. I have three ounces, so far. Well. Three and a half, by now. I get something like a millilitre of molten gold out of the reactor per day, and--"

"SHOW ME WHERE THE GOLD IS," demanded Jaquelline.

"Can I see the reactor?" asked Sam. "And your math?"

Sara giggled and blushed. "You remember that power plant I got for a dollar? I've... been working on it. And in it."

The building was more dangerous than the reactor, and Sara had evidently hired crews to make it safer than it started. Renovations were still underway. The reactor itself would have easily filled a squash court, and it ran all the lights in the building.

"I anticipated access difficulties," Sara's unique way of saying she knew she was going to get grounded and not maintain the machine for extended periods of time. "So I automated the entire process. Rainwater gathers on the roof and feeds into the overhead drip to the reactor. And just in case of drought, there's a pump that runs only when the water falls below a certain level. The cooling system runs a double-reserve steam engine and the waste steam goes back into the system. It's super efficient."

A drop of white-hot metal fell into a container. That set off a weight detector, that turned on a conveyor belt that ferried out the old mould and supplanted it with a new one. The old mould went directly into a safe. Through a hole too small for a human hand.

Sara opened it with a keycode. Eight eights.

"That's a ludicrous security code," scoffed Jaquelline.

"Oh, that's just where it's up to in Pi. It changes to the next eight digits after I close it again." She broke the moulds in the safe and lined up the ingots in a neat stack. Then changed her mind and took them out. "Does this pay for my emancipation, Daddy?"

Sam sighed. "I'm fairly certain that your mother will be kinder to you from now on. Especially given that you've turned a dollar into a literal gold mine."

And, indeed, Jaquelline was busily recalculating her options. She turned startlingly sweet and singsonged, "How do you make it make gold faster, dear?"